The nanoindentation technique was used to measure the hardness and Young's modulus of AZ-1350J(TM) photoresist films irradiated with argon (760 keV), nitrogen (760 keV) and helium (380 keV) with fluences ranging from 1 X 10(13) to 1 X 10(16) ions cm(-2). The average deposited energy was in the range of 0.1-80 eV/Angstrom(3). Raman, Fourier transform infrared radiation (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses were used to observe changes in structural and chemical properties induced by irradiation. Fluences of 1 X 10(14) ions cm(-2) started to decompose the film, which was progressively transformed into an amorphous carbon layer structure. This transformation was clearly shown, not only by the Raman spectra, but also by the large increase in the pristine film hardness from 0.45 to 11 GPa and Young's modulus from 6 to 115 GPa after irradiation with the largest fluence. These results are discussed considering the energy density transferred by the ions to the photoresist films.